July 18, 2003 at 9:14 am
hi all,
How would I build a subquery to return different critiria to 2 seperate columns?
thanks
column1 match column1 condition
column2 match column2 condition
July 18, 2003 at 2:25 pm
SELECT a.* FROM TableA a
WHERE
EXISTS
(SELECT * FROM tableB b WHERE a.Column1 = b.column1 AND a.column2 = b.column2)
or
SELECT a.* FROM TableA a
INNER JOIN tableB b
ON a.Column1 = b.column1
AND a.column2 = b.column2
is this what you meant?
July 21, 2003 at 6:44 am
The question is a little vague. If I understand, I recommend checking out derived tables. The derived table is simply another select statement that can use parms and return a column result set. The columns can be used in your primary select and/or in the where clause. Once your select is defined, simply place parens around it, qualify it, Now place it in your from clause, of the primary select. In many cases, this is leaps and bounds more efficient than a subquery.
i.e. SELECT PrimaryTbl.col1, SecondaryTbl.col1
FROM PrimaryTbl JOIN (derived table select) AS tblB ON PrimaryTbl.colx = TblB.coly.....
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